Vitamin B12 can’t be made by the body; instead it must be obtained from food or supplements. Vitamin B12 is found primarily in meat and dairy products, so vegans and strict vegetarians are particularly at risk for a deficiency. Additionally, elderly people who suffer from certain gastrointestinal disorders are at risk because their bodies are unable to absorb the normal type of B12 that is in food. The National Health and Nutrition Examination Survey estimated that 3.2% of adults over age 50 have a seriously low B12 level, and up to 20% may have a borderline deficiency.